78666677 has 2 divisors, whose sum is σ = 78666678. Its totient is φ = 78666676.

The previous prime is 78666671. The next prime is 78666697. The reversal of 78666677 is 77666687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78127921 + 538756 = 8839^2 + 734^2 .

It is a cyclic number.

It is not a de Polignac number, because 78666677 - 2⁴ = 78666661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78666671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39333338 + 39333339.

It is an arithmetic number, because the mean of its divisors is an integer number (39333339).

Almost surely, 2^78666677 is an apocalyptic number.

It is an amenable number.

78666677 is a deficient number, since it is larger than the sum of its proper divisors (1).

78666677 is an equidigital number, since it uses as much as digits as its factorization.

78666677 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3556224, while the sum is 53.

The square root of 78666677 is about 8869.4237129590. The cubic root of 78666677 is about 428.4797169418.

The spelling of 78666677 in words is "seventy-eight million, six hundred sixty-six thousand, six hundred seventy-seven".